1 Canadian Nuclear Safety Commission Commission canadienne de sûreté nucléaire Julie Mecke – Senior Project Officer Shizhong Lei – Geoscience Technical Specialist Presentation to IAEA Technical Meeting on Human Intrusion and future Human Actions in relation to Disposal of Radioactive Waste Vienna, Austria September 2012 Human Intrusion scenarios for Radioactive Waste Management Facilities – Regulatory Guide and Practices in Canada

2 Overview 1.Existing Regulatory Guidance on Human Intrusion: Regulatory Guide G-320 (2006) “Assessing the Long-Term Safety of Radioactive Waste Management” 2.Examples of proposed Human Intrusion (HI) scenarios for; Port Hope Long-term Waste Management Facility - Surface facility for low-level radioactive waste – licensed, but not constructed Deep Geological Repository for low & intermediate-level radioactive waste – undergoing regulatory reviews Conceptual Deep Geological Repository for Used Nuclear Fuel (Spent Fuel) – no licence application, looking for site 3.Conclusions

3 Canadian Nuclear Safety Commission (CNSC) Regulates… Uranium mines and mills Uranium fuel fabricators and processing Nuclear power plants Waste management facilities Nuclear substance processing Industrial and medical applications Nuclear research and educational Export/import control Radioactive waste management facilities …From Cradle To Grave

4 Regulatory Guide G-320: Assessing the Long-Term Safety of Radioactive Waste Management Published in December 2006 Scope: - Long term care and maintenance considerations; - Setting post-decommissioning objectives; - Establishing assessment criteria; - Assessment strategies and level of detail; - Selecting time frames and defining assessment scenarios; - Identifying receptors and critical groups; and - Interpretation of assessment results.

5 Regulatory Guide G-320 on Human Intrusion 1.Scenarios of inadvertent intrusion should estimate the exposure of the intruder not aware 2.Risk Scenarios should be case-specific 3.Doses should be predicted Both the likelihood and the risk from the intrusion should therefore be reported 4.Reasonable efforts to limit dose from a high- consequence intrusion scenario, and to reduce the probability of intrusion occurring

6 Example 1 – Port Hope Area Initiative (PHAI) Port Hope Long Term Waste Management Facility (LTWMF) Cleanup and safe long-term management of approximately 2 million cubic metres of historic low- level radioactive waste. LTWMF Construction expected Source: AECL,

7 PHAI – Port Hope Long-term Waste Management Facility (LTWMF) –Engineered Mound

8 Port Hope LTWMF – Human Intrusion (HI) Scenario 1 Construction and occupation of residence on Long- term Waste Management Facility (LTWMF) Excavate through cover layers to build house foundation on top of MCS; Occupant spends 75% of the time indoors in the home, with 60% of that time on the main floor and 40% in the basement. Pathways: Gamma radiation and radon from radionuclides in MCS or LLRW

9 Port Hope LTWMF – HI Scenario 1 Construction and occupation of residence on LTWMF

10 Port Hope LTWMF – HI Scenario 2 Exposure to Marginally Contaminated Soil (MCS) /Low Level Radioactive Waste (LLRW) during excavation Cut 4 m x 4 m square area through the cover to the MCS or LLRW One person on a backhoe and one person watching; MCS (or LLRW) exposed for 3 hrs; Backfilled the hole with 1 m of clean soil; remain for 1 more hour after backfilling.

11 Port Hope LTWMF – HI Scenario 2 Exposure to MCS/LLRW during excavation

12 Port Hope LTWMF – HI Scenario 3 Exposure to LLRW removed from LTWMF - Excavate a bulk sample of LLRW rectangular cube 2.5x2.5x1.6m; - Intruders: a backhoe driver and a spotter (on foot), no shielding, 1m away from waste for 4 hrs and 2m away for 4 hrs. Principal exposure pathways: External exposure to gamma radiation, and Inhalation of radon gas released to air from the waste deposit.

13 Port Hope LTWMF – HI Scenario 3 Exposure to LLRW removed from LTWMF

14 Deep Geological Repository - Ontario Power Generation for its L&ILW (OPG DGR) Deep geological repository for OPG’s operating Low- and intermediate- level radioactive waste

15 OPG DGR

16 OPG DGR Source: OPG

17 OPG DGR – HI Scenario Source: OPG

18 OPG DGR – HI Scenario Source: OPG

19 OPG DGR – HI Scenario Source: OPG

20 OPG DGR – HI Scenario Source: OPG

21 OPG DGR – HI Scenario Source: OPG

Conceptual DGR for Canada’s Used Nuclear Fuel – NWMO APM Project Nuclear Waste Management Organization (NWMO) Established in 2002 in accordance with the Nuclear Fuel Waste Act (NFWA) to assume responsibility for the long-term management of Canada’s used nuclear fuel. Adaptive Phased Management (APM) Currently in site selection process No licence application Early regulatory involvement Review of conceptual design and post-closure safety assessment reports for two hypothetical but realistic sites (crystalline or sedimentary rock) Presentations to communities, media, municipal forum groups on CNSC’s early role in the APM Project

23 Example of future HI review – NWMO APM Project Site unknown so conducting pre-project conceptual design for sedimentary and crystalline Final Crystalline conceptual design to be submitted December 2012 and Sedimentary in April 2013 CNSC to review for regulatory issues of concern and issue high-level statement Any statements do not fetter future licensing decisions Requirement for HI scenarios to be included in future licence application “Living” Safety Case - HI - If willing and informed site found in suitable rock, the idea would be for the NWMO to use similar methodologies as in pre-project and look at international best practices/ documents

24 Example of future HI review – NWMO APM Project Preliminary review of conceptual design - Crystalline Preliminary review of draft 2011 “NWMO Interim Pre-Project Report Used Fuel Repository Conceptual Design and Post-closure Safety Assessment in Crystalline Rock” Proposed Human Intrusion Scenario An exploratory borehole is drilled through the geosphere and into the repository. The drill bit is assumed to intersect a used fuel container. The drill crew, exposed to contaminated drill slurry spread on the surface around the drill rig and to a core section containing used fuel; and A resident at the site, exposed by living nearby and growing food on soil contaminated by drill slurry.

25 Human Intrusion is likely one of the scenarios to cause the highest dose to the critical group Important topic for stakeholders – asked at outreach meetings Current CNSC regulatory guide (G-320, 2006) is high-level Development of future regulatory guidance International co-operation to develop a guide on developing credible and conservative human intrusion scenarios is very important for the CNSC. Support international workshop - long time scales of projects – important to keep knowledge management of this topic and to learn from other countries Saskatoon, January Concluding Comments

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